Vestibular rehabilitation therapy (VRT) is currently utilized in the medical arts to treat a variety of vestibular maladies, such as benign paroxysmal positional vertigo (BPPV), labyrinthitis, vestibular neuritis, and the unilateral or bilateral vestibular hypofunction (reduced inner ear function on one or both sides) that is commonly associated with Ménière's disease. However, VRT is believed to work best in the treatment of stable vestibular maladies. VRT is also useful in treating patients with an acute or abrupt loss of vestibular function subsequent to surgery for vestibular problems. In some cases, it is found that patients with long-term, unresolved inner ear disorders, who have undergone a period of medical management with little or no success, may also benefit from VRT.
Vestibular problems affect the vestibulo-ocular reflex (VOR), which controls eye movement and gaze stabilization during head movement, and may also affect the vestibulospinal reflex (VSR), which influences postural stability. Consequently, one of the goals of VRT is to improve these reflexes. VRT does not repair the damaged inner ear, but focuses instead on helping the central nervous system to adapt to the asymmetrical input from the VOR and VSR. Without wishing to be bound by theory, such adaptation may occur through the spontaneous rebalancing of tonic activity in the vestibular nuclei, or by the recovery of the VOR through adaption or by way of the abituation effect (which lessens the response to the same stimuli over time).
VRT typically includes three main approaches: canalith repositioning, substitution and adaption. Canalith repositioning is an option for patients having BPPV in conjunction with labyrinthitis, and involves repositioning calcium crystals into the correct inner ear canal.
Substitution involves strengthening the vestibular system by reducing other inputs such as, for example, vision. In this approach, an exercised regime may be prescribed, but may be performed, for example, with the eyes closed.
Adaption is designed to reset the VOR. Typically, this is accomplished through an exercise regime which features head positions and movements the patient has been avoiding. Many of the exercises feature head movement with eye movement, and often utilize different surfaces. For example, the patient may start an exercise session standing on carpet, and then progress to foam during the exercise. Adaption aids rehabilitation by causing the vestibular system to work harder.
It will be appreciated from the foregoing that, in substitution and adaption approaches, VRT is frequently implemented as an exercise-based program designed to promote central nervous system compensation for inner ear deficits. In a typical VRT regimen of this type, a qualified physical therapist or occupational therapist performs a thorough evaluation that includes an examination of the patient's medical history and an assessment of the patient's VSR. This assessment includes observing and measuring posture, balance and gait, and compensatory strategies. The assessment may also include eye-head coordination tests that measure how well a person's eyes track a moving object (with or without head movement). The therapist may also administer a suitable questionnaire designed to measure the frequency and severity of symptoms and associated lifestyle changes.
Using the evaluation results, the therapist will develop an individualized treatment plan that includes specific head, body, and eye exercises to be performed both in the therapy setting and at home. These exercises are designed to retrain the brain to recognize and process signals from the vestibular system and to coordinate them with visual information and proprioception. This often involves desensitizing the balance system to movements that provoke symptoms, and increasing home-based activities and exercise in order to strengthen muscles. Home exercises are often a vital part of treatment, and the therapist will frequently design an individualized treatment plan with appropriate exercises to be performed by the patient at home at a prescribed pace.